In May or June, you can get some of the best halibut fish and chips at Charlie's Restaurant in Anacortes. Charlie's is located right next to the ferry terminal, so if you park your car and have an hour or so before loading, walk over and pick up some halibut to go and eat it on the ferry.
I lived in Homer, Alaska which billed itself as the Halibut Capital of the World. I watched boats unload huge catches of these giant fish. I saw seasoned deck hands filleting halibut with the skill and precision of a surgeon and I ate amazing halibut fish and chips at nearby eateries. It may be possible that I am a halibut snob.
So, with that "resume" please accept my recommendation for the halibut fish and chips at Charlie's Restaurant. You will not be disappointed. (Unless you don't like to eat fish).